Dressing mechanism



A.141125, 1944. w. B. LOCKE 2,340,192

n DRESSING MECHANISM l Filed Jari. 1,. 1942 2 sheets-sheet 1 17\\ 2a 27" 66 7o 69 1454 64 I5 65 azi |11! Y I* 27 l ul v l l' nur 20 /4 1 if Y .Z6 j 5 2, y 0/ 6 n Jzvenow s y WzZZza/niocke 6/ l BY 7 j' Jan. 25, 1944. w', BVLOCKE 2,340,192

DRESSING MECHANISM Filed Jan. 1, 1942 2 sheets-"sheet 2 l, y 1%94- 4f 6a @#55596 47a 4a QP# Patented Jan; 25, 194e IiRESSING MEGHNHSMv William B. Locke, Detroit, Mich., assigner to m- Cell-O Corporation, Detroit, Mich., a corporation of Michigan Application January l, 1942, Serial N0. 425,29

(Cl. 12S-11) 15 Claims.

The present invention relates to improvements in dressing mechanisms for grinding wheels and has particular reference to a dressing mechanism for dressing a single rib thread form on the external periphery of a grinding Wheel adapted for use in thread grinding machines to grind a complemental thread form on the periphery of a workpiece. v

One of the objects of the invention is to providea novel dressing mechanism includingvan adjustable sine bar for translating the dressing tool in one direction and cam means for simultaneously translating the dressing tool in a perpendicular direction so as to cause the tool to describe a path of predetermined configuration.

Another object is to provide a new and improved dressing mechanism of the foregoing character including a lost motion connection between the sine bar and the dressing tool so that the paths of movement of said tool in opposite directions will be similar but Adisplaced from each Other objects and advantages will become apparent as the description proceeds.

In the accompanying drawings:l l

Figure l is a plan view partially in section along line I-i of Fig. 2 oi a dressing mechanism embodying the features of my invention.

Fig. 2 is a side elevational view partially in vertical section along line 2-2 of Fig. 1 of the dressing mechanism.

Fig. 3 is a vertical sectional view taken along line 3--3 of Fig. 2.

Fig. 4 is a fragmentary vertical sectional view A taken along the broken line of Fig. 2.

Fig. 5 is a fragmentary detail sectional view takenalong line 5 5 of Fig. 4.

active 'relation with the periphery of a grinding wheel W, and has two dressing tools T1 and T2 for dressing the opposite flanks l and 2 of thewheel. The periphery of the grinding wheel W" is generally of v contour, but itis to be understood that the specic contour may be varied as required for grinding threads of different forms, such as sharp V, U. S. Standard, Acme, Whitworth, etc. Thus, theperiphery may be sharp,

truncated or rounded at the apex and also at the base. Y

The dressing mechanism comprises a base plate 3 having spaced iront and rear pedestals d and 5.

Figs. 6 and 7 are fragmentary plan views of) the dressingmechanism illustrating the cycle of operation.

While the invention is susceptible of various modications and alternative' constructions, I have shown in the drawings and will herein describe in detail thepreferred embodiment, but it Y is to be understood that I do not thereby intend to limit the invention to the specic form disclosed, but intend to cover all modications and alternative conructions falling within the spirit and scope of the invention as expressed in the appended claims.

Referring more particularly to the drawings, the dressing mechanism constituting the exemplary embodiment of the invention is adapted to be mounted as a unit on a suitable support, such as a dresser slide (not shown), for movement into end of the spring iS-abuts against a pin l5-pro f The front pedestal d supports the dressing tools Y T1 andl T2 for joint movement generally longitudinally of the axis of `the grinding wheel W, l.

and for independent movement generally transversely of the axis, so that each tool describes a path which is the resultant of two movements. By varying the component movements, various congurations are obtainable on the'wheel W to grind any desired complementary thread form in the work.

The tool support comprises a riser block B xed on theV pedestal d, and formed at the top with a dovetail guideway l extending generally longitudinally of the grinding wheel axis. A slide is mounted on the 'block 6, and has a dovetail guide 9 adiustably disposedwithi'n the guideway l. The longitudinal slide'8 is formed in the top with two parallel dovetal guideways IG extending transversely of the guideway l. Two similar tool' slides l i are mounted on the slide Y8, and haveA dovetail guides I2 slidably disposed in the guide- .ways I6. Each of the slides H is-urged resiliently in a direction away from thegrinding wheel W. In the present instance, the meansior this purpose comprises a coil compression spring i3 disposed within a longitudinal groove i4 in the underside of the associated slide. The forward jecting upwardly from the longitudinal slide 3, and the rear .end abutsagainst the rear end of the groove i5. y

The forward end portion of each transverse slide il is formed with an upstanding externally threaded boss or projection I6 supporting a dressing tool holder Il for swivel-adjustment. A cylindrical body or post i8, having a diametrical bore i9, is mounted vertically on the projection V it. The post i8 has a circular base flange 2li conned in .position 'for rotary or swivel adjustment by means of a ilanged'nut 2l threaded onto the projection l5. Projecting axially from the upper end of thepost I8 is a threaded stud 22.

A tubular spacer 23, having diametrically opposite openings 24 in alinement with the bore I9, encircles the post I8, and bears at its lower end against the top of the nut 2I. The upper end of the spacer 23 has an internal ange 25 encircling the stud 22, and engaging over the upper edge of the post I8. A lock nut 26 is threaded onto thestud 22' against the flange 25, and when tightened serves to secure the holder I1. rigidly I in position of angular adjustment.

A sleeve 21 extends through the bore I9 in the post I8 and the openings 24 in the spacer 23,

28. 'Ihe sleeve 21 is formed with an axial bore 29 which at the forward end is slightly reduced in size to provide a guide 30. Projecting slidably through the guide 30 into the bore 29 is a toolshank 3I with a iiat face 32 in the top side and an axial threaded bore 33 in the inner or rear.

end. One of the diamond dressing tools T1 or T2 is conventionally mounted on the projecting forward end of the shank 3l. A locking screw 34 extends from the top axially through the post I8 into end engagement with the flat face 32, and serves to confine the shank 3| against rotation and when tightened to lock the shank rigidly in axial position. Rotatably confined by means of a key 35 in the rear end of the bore 29, and having a head 36 bearing against the rear end of the sleeve 21, is an -adjusting screw 31 in threaded engagement with the bore 33 in the inner end of the tool shank 3 I It will be understood that the two tool holders I1\ are alike in construction. In each instance, the tool-shank 3l' may be adjusted axially by releasing the screw 34 and rotating the screw 31, and then may be locked in adjusted position by tightening the screw 34. Also, the tool shank 3I may be adjusted' into the proper angular position in relation to the grinding wheel W by loosening the nut 26 and swiveling the post I8. When the nut 26 is tightened, the plug I8 is securely locked in position. Since the two tools T1 and T2 are arranged respectively to dress the inclined flanks I and 2 of the grinding wheel W, they are normally inclined in opposite directions so as to provide cutting clearance.

The dressing tools T1 and' T2 are translated through their cycles by an actuating mechanism 38 mounted on the rear pedestal 5, and coactingwith the longitudinal slide 81 and the transverse Vvslides I2. Each tool is caused to dress the related flank only upon movement from the apex to the base ofthe wheel form, and to avoid contact -with the'ank during the return movement. The two tools are arranged to dress the related wheel flanks in alternate strokes, so that as either tool moves inwardly in its dressing stroke, the other tool moves outwardly in its free return stroke,

In its preferred form, the actuating mechanism having a hand wheel 44. The screw 43 extends through threaded engagement with a nut 45 on the rear of the slide 4I.

The actuating slide 4I carries an angularly adjustable sine bar 46 for translating the longitudinal tool slide 8, -and two cam bars 41. and .43

of selected contour for translating or controlling the transverse tool slides II. It will be understood that the angular disposition of the sine bar 46 and the shape of the cam bars 41 and 48 determine the coordinated actuation of the slides 6 and II, and therethrough the contour produced on the grinding wheel W by the dressing tools T1 and T2. y Y

The sine bar 46 is disposed against the flat front face of the slide 4I, and has a pivot-pin 49 substantially midway of its ends. This pin e x and is located in endwise position by a shoulder tends rotatably into a bore 50 in the front of the slide 4I, and -is formed with a peripheral splinegroove 5I. A locking pin 52 extends vertically through the slide 4I into the groove 5I, and is adapted to be tightened by a lock screw 53. When the screw 53 is released, the sine bar 46 may be adjusted into the desired angular position.

To locate and hold the sine bar 46 accurately in adjusted position before tightening the pin 52, one side of the bar is formed with an abutment surface 54 adapted to `be held against the periphery of a gauge vdisk 55 of selected diameter removably mounted on a pin 56 on the front of the slide 4I. The size of the gauge disk 55 for given cams 41 and 48 determines the angularity of the sine bar 46, and hence the included angle between the flanks I and 2 of the wheel W. For example, a gauge disk 55 of a given diameter will result in an included angle of 30.' Another disk of larger outside' diameter will resultv in an included angle of 60. By appropriate selection of disks of different diameters, diierent included angles are obtainable.

The surface 54 is held temporarily against the gauge disk 55 by means of a latch member 51 in the form of a wedge-shaped plate having a hook 58 on one end adapted to engage the opposite side edge of the sine bar 46. The plate 51 is slidably adjustable on the upper inclined end surface 59 of the vertical slideI 4I, land is formed with a longitudinal slot 60. A clamp bolt 6I extends through the slot 60 into threaded engagement-with the slide 4I, and when tightened serves to secure the latch member 51 in position of adjustment. When the s ine bar 46 is accurately located, the screw 53 is tightened to force the pin 52 into the groove 5I. The rear side of the groove 5I and the corresponding side of the pin 52 are'Wedge-shaped so that the sine bar 46 is clamped tightly against the front faceof the slide 4I.

The sine bar 46 is formed on its front face with a medial longitudinal rib 62.of uniform truncated triangular form in cross section. The rib 62 is adapted to engage in a notch or bifurcation 63 of complemental shape in the rear end of the plate 64 on the longitudinal tool slide 6. In the present instance, the plate 64 is mounted on the slide 8 between the tool slides II for selective adjustment toward and from the sine bar 46. A bolt 65, extending through a longitudinal slot 66 in the plate 61| into threaded engagement with the vslide 8, serves when tightened to secure the plate rigidly in adjusted position.

It will be evident that upon vertical movement of the sine bar 46, the slide 8, and hence the dressing tools T1 and Ta, will be translated crosswise of the grinding wheel W. Upon downward movement of the bar 46, one side thereof will engage the adjacent side of the notch 63 to move the slide 8 from right to left (Fig. 6). Upon upward movement of the bar 46, the opposite side thereof will engage the other side of the notch 63 to move the slide 8 from left to right (Fig. 7).

radial retraction of the respective The notch 63 is somewhat wider than the rib l(i2, although the sides of the two. have substantially the same included angle. Consequently, a lost motion is provided between the rib '62 and the plate 64. 'l'h'is lost motion is eiective at each reversal of the'sine bar I6 to cause the longitudinal tool slide 8 to dwell untilthe inclined riblZ in its reverse movement engages the opposite side of the notch 63. The lost motion may be varied as desired by alusting the plate Si to alter the depth or degree of engagement between the rib 62 and the notch 63.

The cams 4l and 48 for actuating the tool slides ll consist of flat plates adiustably secured to opposite sides of the vertical slide 4I, and formed on the forward edges with longitudinal cam faces dla and d8a of desired conguration. Preferably, each of the cam plates 41 and B8 is seated for longitudinal adjustment in a square vertical notch Bl in one side or the other of the slide 4l, and is formed with two longitudinal slots 68. A side plate 69 is positioned against the cam plate within the notch 61. Bolts 1D carried by the side plate 69 extend through the slots 68 into Y threaded engagement with the slide 4I, and when sequently, vertical movement of the cam plates d1 and 48, with the sine bar 4E, by the slide 4I,

will cause the tools T1 and T2 to move in a predetermined pattern.

The cam faces 41a and 48a are opposltely in- 4 clined so that as one tool moves inwardly in its cutting stroke, the other tool moves outwardly in its free return stroke. Thel configuration may be varied as requiredto form the flanks l and 2 of the grinding Wheel W to grind a complemental thread of any desired form inthe workpiece. In

the present instance, the cam faces 41a and 48a are straight and inclined. The side plates 69 also have a cam flmction and determine the maximum dressing tools Ti and Tz.v More particularly, they have straight vertical faces 69a along their forward edges. By

adjusting the cams 41 and I8 longitudinally, as

permitted by the slots 68, the ends of the faces 69a at the points of greatest retraction of the I faces "aand 48a can he arranged todeine ver-` -tical end portions, varying in extent from zero to maximum, for controlling the position of the dressing tools when fully retracted. Asslnning thatthecamsll and areadju'stedasshown inliig.2toutilizetheendsofthefaces69a,these camsandtheplates iwillcausetlletoolstopr ducea truncated form with l and 2 on the wheel W. The degree of adjustment will determine the width of the end face on the form. Ifthecamsll andllareadjustedtoremain fullyincontrol,avformwllbeproducedonthe wheel W.

In operation, assume that the slide 4l is in iis lowermost position.. In this position, the dressing toolTiislocated atthe'baseoftheank Land the tool T2 is located in fully retracted position to the left of the dat face of the wheel W. VUpon tionary until the lost motion between the sine rib 62 and the groove 63 is taken up. During this dwell period, the tool Ti is retracted from the ilank I. 'In the contlnued movement of the slide BI, the slide B is moved from leftto right (Fig. "I) and the tool Ti is simultaneously moved outwardly in parallel spaced relation to the dank l. The tool T2 is shifted across the flat or trlmcated face of the grinding wheel W, and is then moved inwardly to dress the flank 2 from the apex to the base. During the end portion of this movement, the tool Ti is moved across the at or truncated face of the wheel W.V It will be understood that the movementr of the tools Ti and T2 across the end face is controlled by the vertical end portions of the cam faces 41a and d8a,

-and that the radial movement thereof is conllation along the flank 2 and then across the reversing the screw 4s to initiate the uinlvaruV movement of the slide Il, the slide 8 remains staend face of the 'wheel W into initial position, and simultaneously the tool Ti is moved across the end face and then inwardly to dress the dank I from the apex to the base (Fig. 6)

I claim as my invention:

l. A dressing mechanism for a rotary grinding wheel comprising, in combination, a support, a rst slide mountedfor reciprocation on said support longitudinally of the grinding Wheel axis, a cross slide mounted for reciprocation on said first slide transversely of said axis, a post mounted on said cross slide for angular adjustment 4about an axis perpendicular f to said slides and being= formed with a diametrical bore, means for clamping said post in position of adjustment, a tool shank supporting a dressing tool and extending into said bore, means for adjusting said toolv` wheel comprising, in combination. a support, a'

first slide mounted for reciprocation on said support longitudinally of the wheel axis, v

a cross slide molmted for reciprocation on said rst slide transversely of said axis, a tool'holder lmounted on said cross slide for angular adjustmen't about an axis perpendicular-to said slides,

means for clamping said holder in position o'f ro.

tary adjustment, a tool shank supporting a dressing tool and mountedon said holder, means for adjusting said tool shank on said holder transversely of the axis of said holder, and operating means for translating said slides simultaneously in predetermined timed relatin.

3. A dressing mechanism for a grinding wheel comprising, in combination, a support, a :drst slide mounted on said support for movement generallyinthe direction of thewheel axis, asecond slide mounted on said iirst slide for movement generally perpendicularwto said a third slide mounted on said support for movement perpendicularly to said rst mentioned slides, a longitudinal sine bar molmted on' saidV third slide for' pivotal adjustment into different relative angular positions and having a ribcoacting with rectilinear cam member mounted on said third Again, the lost motion is taken up slide and coacting with said second slide in all positionsoi said rst slide to actuatesaid second slide in timedelation to the movements of said third slidei 4. A dressing mechanism for a grinding wheel comprising, in combination, a support, a iirst slide, a longitudinally inclined sine bar mounted on said third slide and' coacting with said rst slide to actuate the latter in timed relation tp the movement of said third slide, and a cam member mounted on 'said third slide and coacting with said second slide in all positions of said first slide to actuate said second slide in timed relation to the movements of said third slide.

5. A dressing mechanism for a grinding wheel comprising, in combination, a support, a slide mounted on said support for reciprocation in a predetermined direction, a dressing tool mounted on said slide, a plate mounted on said slide ior transverse adjustment and being formed in one end with a truncated V-shaped notch, a second slide mounted on said support for reciprocation perpendicularly to said iirst mentioned slide, a longitudinal sine bar mounted on said second slide and having a truncated triangular rib engaging in said notch, said rib being complemental inshape to but narrower in width than sine bar having a pivot intermediate its ends rotatableyin said second slide and formed with a peripheral wedge groove, a removable gauge disk on said second slide for locating said sine bar in selected angular position, adjustable means for confining one edge of said bar against the periphery 'of said disk, and wedgemeans engageable with said groove to clamp said sine bar securely against said second slide.

9. A dressing mechanism for a grinding wheel comprising, in combination, a support, a rst slide mounted on said support for reciprocation generally longitudinally of the grinding wheel axis, a second slide mounted on said rst slide for transverse movement, a dressing tool havingl a shank mounted on one end of said second slide for angular adjustment, the other end of said` second slide havingY a straight lateral edge' of rounded form, a third slide mounted on said support for movement perpendicularly to said rst and second slides and said edge. a longitudinal `cam member mounted on said third slide and having an inclined face engaging said rounded edge of said second slide to actuate the latter, means for malntainingsaid edge against said cam, and means operated in timed relation to said third slide for reciprocating said firstv slide.

said notch whereby to provide a lost motion engagement, the adjustment of said plate permitting variation of said lost motion, and means for reciprocating said -second slide, with said first slide dwelling at each reversal during the takeup oi.' said lost motion.

6. A dressing mechanism for a grinding wheel comprising, in combination, a support, a slide mounted on said support for reciprocation in a predetermined direction, av dressing tool mounted on said slide, means on said slide defining ak notch, a second slide mounted on said support for reciprocation perpendicularly to said rst mentioned slide, a longitudinally inclined sine bar'mounted on said second slide and having a rib engaging in said notch, said rib being narrower in width than said notch whereby to prog-vide a lost motion engagement, and means for reciprocating said second slide, with said rst cating said sine bar in selected angular position,

and wedge means engageable with said groove to clamp said sine bar securely against the face of said second slide.

8. A dressing mechanism for agrinding wheel comprising, in combination, a support, a iirst slide mounted on said support, a 'dressing tool mounted on said slide, a second slide mounted on said support for movement DerDendicularly to said rst slide, a sine bar mounted on said sec- .ond slide and coactins with said irst slide. saidr axis, a second slide mounted on said rst slide for transverse movement, a dressing tool having a shank mounted on one end of said second slide for angular adjustment. the other end of said 'slide mounted on said support `for 'movement longitudinally of the -wheel axis, two paralleldresser slides mounted on said rst slide for independent movement transversely thereof, two dressing tools mounted respectively on said- 'dresser slides for angular and radial adjustment, an actuating slide mounted on said support for movement perpendicularly to said rst slides, an angularly adjusted sine bar mounted on said actuating slide and coacting' with said rst slide to reciprocate the latter, two parallel 'cams mounted on said actuating slide and co acting with said dresser slides to reciprocate the latter in any position of said rst slide, spring means for maintainingsaid dresser slides in ensagement with said cams. and means for reciprocating saidactuating slide. A

l2. A dressing mechanism for a grinding wheel comprising, in combination, a support, a rst slide mounted on said support, aV second slide mountedon said rst slide forlmovement in a perpendicular direction, a third slide mounted on said support for movement perpendicularly to said first mentioned slides, a dressing tool carried by said second slide, means on said third,

slide coasting with said rst slide to reciprocate the latter generally longitudinally of the wheel axis, and Atwo cam bars mounted on said third slide for relative longitudinal .adjustment and co acting with said secondslide to actuate the latter in timed relation to said first slide, one of said cam bars having a congurated cam face and the other of said cam bars having a longitudinal cam face adapted in various positions of relative adjustment between said faces to constitute an extension of saidy one face to determine the point of maximumretraction of said tool radially of said wheel,

tory movements of said Aiirst and second slides,v

and means for reciprocating said third slide.

14. A dressing mechanism fora grinding wheel comprising, in combination, a support, a iirst slide mounted on said support for movement generally in the direction of the wheel axis, a

second slide mounted on said iirst slide for movement generally perpendicular to said axis, a third slide mounted on said support for movement perpendicularly to said first mentioned slides, means on said third slide engaging said rst and second slides for translating the reciprocatory movement of said third slide into the respective reciprocatory movements of said rst and second slides, and means for reciprocating Isaid third slide, the translating means between said third and rst slides including a 10st motion relationship.

15. A dressing mechanism for a grinding wheel comprising, in combination, a support, a first slide mounted on said support for movement generally in the direction of the wheel axis, a second slide mounted on said iirst slide for movement generally prependicular to said axis, a third slide mounted on said support for movement perpendicularly to said rst mentioned slides, means on said third slide engaging said first and second slides for translating the reciprocatory move- /ment of said third slide into the respective reciprocatory movements of said rst and second slides, means for reciprocating said third slide, and means for modifying the-movement imparted to the second slide by the translating means between the second and third slide.

' WILLIAM B. LOCKE. 

